These inventions relate to traffic control and warning systems, and, in particular, to traffic control and warning systems that incorporate the use of fuzzy logic or other expert systems.
Present methods of controlling traffic are in need of improvement. One area needing improvement is the method of controlling traffic lights. A significant amount of time is wasted while waiting for a traffic light to turn green. Motorists are oftentimes forced to wait at a red light while there is little or no cross traffic. This type of situation often causes drivers to become very impatient or frustrated. Angry and frustrated drivers are dangerous and are more prone to cause accidents. People not only waste precious time while waiting for traffic lights to turn green but also while sitting idle in traffic congestion or traffic jams. Again, these situations cause certain drivers to become very angry and frustrated.
Traffic flow can also be improved by providing motorists with real time, relevant traffic information. Many times, traffic information is available via local radio stations. Radio stations do not, however, necessarily provide real time information. Thus, motorists often find themselves caught in a traffic jam before the radio station is able to inform them of the traffic situation. Moreover, the current traffic information provided by local radio stations may not be relevant for some specific drivers, particularly drivers at different geographic locations or headed in different directions. Also, the radio traffic reports are generally for commuters who travel via freeways or highways and are generally not for drivers in neighborhoods and on smaller/local streets and roads. The lack of localized traffic information prevents motorists from avoiding local traffic jams or congestion areas that are not reported by the radio stations. Therefore, improved methods of controlling traffic lights and providing real time, relevant traffic information to motorists based on their location and travel direction are needed and desired.
Present traffic warning signs are confined to freeway applications. Such signs do not use fuzzy logic or expert systems analysis with real time updates based on traffic light phase splits, real time traffic analysis, or GPS based location calculations of sign and traffic congestion or locations of other problems. Present systems also do not use portable signs with GPS receivers to calculate locations and then use the calculated locations in determination of information to be displayed.
Furthermore, there is a need for traffic control and warning systems and methods that optimize traffic flow based on traffic patterns and other factors. There is a need to integrate control information into comprehensive motor vehicle warning systems and methods that warn or advise drivers of situations that should be avoided.
The present invention uses fuzzy logic or expert system algorithms and GPS technology to provide an improved, integrated system and method for controlling traffic lights and traffic flow and to provide current, real time, up-to-date, relevant traffic information to motorists.
Several prior art patents address different aspects of traffic control and warning systems. For example, it is known to compile and evaluate local traffic data via radar. See, e.g., U.S. Pat. Nos. 4,985,705; 5,041,828; 4,908,615.
It is also known to use cameras to monitor traffic violations and record traffic statistics. See, e.g., U.S. Pat. Nos. 5,432,547; 5,041,828; 5,734,337.
It is also known to detect vehicles approaching an intersection. Furthermore, it is known to warn motorists at intersections of approaching vehicles. See, e.g., U.S. Pat. Nos. 5,448,219; 5,572,202, and French Patent No. 2562-694-A.
It is also known to modify traffic control information via circuit arrangements. See, e.g., U.S. Pat. No. 4,352,086.
It is also known to control traffic lights based on the conservation of aggregate momentum. See, e.g., U.S. Pat. No. 4,370,718.
It is also known to control traffic and traffic signals based on local requests for service. See, e.g., U.S. Pat. No. 4,322,801.
It is also known to control traffic and traffic signals based on the detection of vehicles and pedestrians at an intersection. See, e.g., German Patent No. DE 2,739,863.
It is also known to control traffic and traffic signals on a local level in conjunction with an area-wide traffic control system. See, e.g., U.S. Pat. No. 5,257,194.
It is also known to alert motorists of traffic situations via the use of real-time traffic images. See, e.g., U.S. Pat. No. 5,396,429.
It is also known to use scanning transmissometers to warn motorists of decreased visibility. See, e.g., U.S. Pat. No. 5,771,484.
It is also known to provide motorists with accident information based on a vehicle""s current driving conditions and previous accidents that occurred under similar conditions. See, e.g., U.S. Pat. No. 5,270,708.
It is also known to alert motorists via an accident avoidance system that their vehicle is approaching potentially hazardous situations. See, e.g., U.S. Pat. No. 5,652,705.
It is also known to provide motorists with traffic information via a display inside of their vehicle. See, e.g., U.S. Pat. Nos. 5,313,200; 5,257,023; 5,182,555; 5,699,056; and 5,317,311.
It is also known to use cameras to predict traffic flow rates and to use this information to control local traffic. See e.g., U.S. Pat. No. 5,444,442. U.S. Patent No. 5,444,442 does not, however, use fuzzy logic algorithms to control traffic and traffic signals.
It is also known to control traffic and traffic signals via neural networks. See, e.g., U.S. Pat. Nos. 5,459,665; 5,668,717. However, U.S. Pat. Nos. 5,459,665 and 5,668,717 do not use fuzzy logic to control traffic or traffic signals.
It is also known to transmit traffic signal information to motorists via radio transmission. See, e.g., Japan Patent No. 3-157799. Japan Patent No. 3-157799 does not, however, distribute the information to motorists via intelligent traffic signs. Furthermore, Japan Patent No. 3-157799 does not use fuzzy logic to selectively distribute or assess the warning information.
It is also known to provide citizens with traffic information via programmable display mediums. See, e.g., U.S. Pat. No. 5,729,214. However, U.S. Pat. No. 5,729,214 does not use fuzzy logic algorithms to selectively distribute or assess the traffic information.
It is also known to control traffic signals by modeling the traffic light phase-splits after stored traffic flow models. See, e.g., German Patent No. 2411716. German Patent No. 2411716 does not, however, use fuzzy logic algorithms to determine the optimum traffic flow.
It is also known to control traffic and traffic signals via fuzzy logic algorithms. See, e.g., U.S. Pat. No. 5,357,436 and Japan Patent No 4-148299. U.S. Pat. No. 5,357,436 and Japan Patent No 4-148299 do not, however, use fuzzy logic algorithms to selectively distribute or assess warning information to motorists.
It is also known to detect traffic using a fuzzy logic processor. See, e.g., U.S. Pat. No. 5,696,502. U.S. Pat. No. 5,696,502 does not, however, use fuzzy logic to control traffic signals and to selectively distribute or assess warning messages.
Each of the patents and articles discussed above is incorporated herein by reference.
None of the above inventions make use of fuzzy logic or expert systems to determine the distribution of traffic or danger warning information. This method of distribution is described below in detail. The use of fuzzy logic algorithms to selectively distribute relevant information to motorists, in conjunction with the use of fuzzy logic to control traffic and traffic lights creates an improved, comprehensive traffic control and warning system and method. The present invention derives control parameters for traffic lights and traffic-warning signs based on past and current real time traffic flow parameters. The present invention also warns drivers of vehicles of situations to be avoided, thus permitting individual driver actions that will minimize future aggravation of congestion or dangerous traffic situations. Centralized and distributed fuzzy logic calculations are used to derive control and warning message parameters. These calculations are arranged to respond to past traffic flows and present traffic measurements and dangerous situations, and to minimize future aggravation of situations of concern.
The present invention is a system and method for controlling traffic and traffic lights and selectively distributing warning messages to motorists. Fuzzy logic is used to dynamically derive traffic light phase-splits (i.e. the time split between red and green for a given traffic light cycle) based on traffic flow patterns and other factors such as weather conditions, predicted increases in traffic for rush hour or special events, etc. Warning signals are also broadcast to motor vehicles and/or to fixed or portable traffic warning signs. The GPS coordinates of the vehicles and/or signs are known or are calculated from received GPS satellite signals. The warning messages may include unusual traffic light phase-splits, traffic congestion information, dangerous situation information including fuel or chemical spills, accident information, etc. Fuzzy logic controllers in signs or in vehicles calculate danger warning signals and deliver appropriate messages to drivers based on the received information and the current GPS coordinates of the vehicle or traffic warning sign. Thus fuzzy logic is used to calculate traffic light phase-splits and also to calculate appropriate danger warning messages based on the calculated phase-splits and other traffic conditions. Fuzzy logic calculations may be made at a central controller or on a distributed basis at the traffic lights, warning signs or in the vehicles. Different combinations of centralized and distributed calculations may also be used. A totally integrated fuzzy logic based expert system and method for traffic flow control results with control of traffic signals and coordinated control of messages to vehicles and signs to further improve traffic flow and relieve congestion results.
The present invention includes various traffic information units that obtain traffic information. The traffic information units have intelligent controllers. The traffic information is transmitted to one or more central controllers. The central controller or controllers is/are used to determine congestion parameters and warning information. The congestion parameters and the warning information are transmitted from the one or more central controller(s) to the intelligent controllers. The intelligent controllers are used to determine appropriate action based on the congestion parameters and the warning information.
The present invention also includes one or more traffic lights with intelligent controllers. The traffic lights with intelligent controllers include receivers that receive and analyze communication signals from a central control, a transmitter that generates and transmits signals to traffic lights with cameras and traffic lights with intelligent signs, and a computer controller including a processor and memory.
The present invention also includes one or more traffic lights with intelligent warning signs. The traffic lights with intelligent warning signs comprise a receiver that receives and analyzes communication signals from traffic lights with intelligent controllers and a warning sign that displays warning messages to motorists.
The invention further includes one or more intelligent road-side warning signs that comprise receivers that receive and analyze communication signals from traffic lights with intelligent controllers or the central controllers, and a warning sign that displays warning messages to motorists. The intelligent road-side warning signs may be at permanent, fixed locations, or they may be portable warning signs. The traffic warning signs have known geographic coordinates, such as GPS coordinates, used to determine which messages to display on which signs. Portable traffic warning signs may include GPS receivers to derive variable location information.
Furthermore, the invention includes one or more traffic lights with cameras that monitor intersections or roads, receivers that receive and analyze communication signals from traffic lights with intelligent controllers, and transmitters that generate and transmit signals to traffic lights with intelligent controllers. Captured video signals may be transmitted to a central control station for evaluation by human operators or for automatic evaluation using image analysis software.
The invention also includes one or more road-side traffic and weather sensors that include transmitters that generate and transmit signals to central controllers.
In addition, the present invention includes vehicle-warning units in motor vehicles. The vehicle warning units include receivers that receive and analyze communication signals from central controllers. The vehicle warning units also include satellite receivers that receive and analyze communications signals from a satellite positioning system and determine current geographic location of the warning unit, transmitters that generate and transmit data to the central controllers, and alarm indicators that indicate relevant traffic situations or emergencies.
Similarly, portable traffic signs and warning signs may be setup to receive information similar or identical to the information that is sent to motor vehicles. That is that a mobile traffic sign may incorporate GPS position location systems to enable it and the central controller to know the location of the movable sign. Given that the signs may be movable, the current position of the sign would be input information helpful in determining the appropriate warning notification sent to the sign for posting on the sign. The information could also be used at the sign for coordinated communications with other mobile signs, stationary signs, or with traffic light controllers as well as with the central controllers.
The invention also includes central controllers. The central controllers include database computers having a database storage unit and processors with memories configured to monitor existing traffic conditions and emergency situations and distribute warning messages. The central controllers also include receivers that receive and analyze communication signals from traffic sensors, traffic lights with intelligent controllers, and vehicle warning units. Furthermore, the central controllers include transmitters that generate and transmit signals to traffic lights with intelligent controllers, vehicle warning units and road-side warning signs.
In operation of the present invention, the traffic lights with cameras transmit images to traffic lights with intelligent controllers, and the traffic lights with intelligent controllers transmit the images to central controllers. The traffic and weather sensors transmit traffic and weather data to the central controllers. The vehicles with warning units transmit data to the central controllers. The central controller receives and processes data from the traffic lights with intelligent controllers, vehicle warning units and traffic sensors and determines the traffic congestion parameters. After determining traffic congestion parameters, the central controller transmits congestion parameters and warning information to the traffic lights with intelligent controllers, the road-side warning signs and the vehicle warning units.
Upon receipt of the transmitted data, the traffic lights with intelligent controllers determine if warning information is applicable to associated intersections and transmits any applicable warning information to the traffic lights to adjust traffic light phase-splits and to warning signs and to the roadside signs. Alternatively, the information for roadside-warning signs may be transmitted directly from the central controller. Upon receipt of the transmitted data, the roadside warning signs determine if the warning information is applicable for the associated sign and displays appropriate warnings. Upon receipt of the transmitted data, the vehicle warning units determine if warning information is applicable to each vehicle and alerts motorists of any relevant warnings.
The present invention uses a Global Positioning System (GPS) system to determine locations of portable signs and vehicles. GPS coordinates are also used to identify intersections, fixed location signs, and coordinates of trouble such as accidents. The satellite receivers of the invention are compatible with the Global Positioning System. The current geographic position of the satellite receivers are defined by the receiver""s GPS coordinates. While the invention is described in terms of GPS technology, it is to be understood that other methods of determining coordinate location information may be used.
In addition, the present invention also includes emergency vehicles with GPS location receivers and processors to precisely locate the vehicle and to report location, movement and destination to the central controller for use in generating traffic management controls.
The present invention includes fuzzy logic controllers. The fuzzy logic controllers execute fuzzy logic inference rules from a fuzzy rule base. The execution of these rules using the defined rule base analyzes traffic congestion and decides on appropriate actions. Appropriate actions may be traffic control action, or it may be appropriate traffic information distribution. The fuzzy logic controllers also use fuzzy logic to derive the warning information based on avoidance level of dangerous situation and distance to dangerous situation and detection of abnormal phase-splits of traffic lights.
Fuzzy logic may be incorporated into the computations at several levels of the traffic control system. A first fuzzy logic calculation would be at the data gathering and phase split determination stage of the traffic control process. Here the fuzzy logic inputs would be, for instance, the volume of traffic that is entering the zone of the intersection and the relative direction and speed of the traffic from several directions. Given these inputs, and there may be many input variables, the calculation will proceed in the generation of the traffic light phase splits. A second fuzzy logic calculation would involve the affect of the phase splits and other input factors such as vehicle speed and direction that would be input into the fuzzy logic calculation. The output of this calculation would be, or could be, advice to a moving vehicle to take certain actions to avoid or minimize vehicle travel to congested or otherwise dangerous locations. Such actions could also be designed considering the phase splits of traffic lights calculated in the first fuzzy logic calculation. These and other aspects of the process are further discussed below.
Fuzzy logic calculations may be made at the central controllers or distributed in the intelligent traffic light controllers, warning sign controllers, or in the motor vehicles controllers. The central controller receives congestion parameters from traffic lights with cameras, from roadside traffic sensors, from weather sensors, and/or from other sources. The central controller may make fuzzy logic calculations based on the received information for transmission. The central controller then may transmit specific traffic light phase-splits to the various traffic lights under its control. The central controller may also transmit specific warning message information to the intelligent road-side traffic warning signs.
Alternatively, the central controller may analyze received traffic congestion information and transmit control parameters to distributed fuzzy logic controllers located at intelligent traffic light controllers and/or in intelligent road-side sign controllers. The respective distributed fuzzy logic controllers then may perform fuzzy logic calculations to derive local control information and/or warning sign information. Distributing fuzzy logic calculations to the actual intelligent traffic light controllers or road-side signs reduces the load on central controllers. In any event, the results of the fuzzy logic calculations are sent back to the central controller to update the controller data base with current statue information reflecting the state of the traffic light phase-splits and the warning sign messages.
The present invention uses fuzzy logic to determine the optimum traffic light phase-split based on the traffic volume parameters at the intersection. The traffic light phase-split fuzzy logic calculation may be made at the intelligent traffic light controller or at the central controller.
Separate additional fuzzy logic calculations are made to warn drivers of individual vehicles of dangerous situations or traffic situations to be avoided. These calculations are best made in controllers located in individual motor vehicles. The operation is as follows. The central controller analyzes received traffic conditions, transmits appropriate traffic light and roadside sign control messages, and maintains a current traffic control database. The central controller broadcasts messages to motor vehicles indicating the locations (GPS coordinates) of traffic congestion, dangerous situations, or areas to be avoided. Also, for each such situation, a numerical avoidance level parameter is transmitted. All vehicles in a given geographic area receive the same broadcast messages from the central controller. Each vehicle also has a GPS receiver to determine its own location and direction of travel. Compasses or accelerometers can also be used to determine direction. The vehicle speed can also be computed from successive GPS readings and/or from vehicle speedometer readings. Based on the received GPS coordinates of each situation to be avoided, the calculated GPS coordinates of the vehicle and the vehicle direction of travel, each vehicle fuzzy logic controller computes a danger warning index for that situation, indicating to the driver the degree of danger presented by each situation. The driver is made aware of situations to be avoided and the fuzzy logic calculated degree of danger or concern by audio announcement or visual message display.
In one embodiment, then, the intelligent traffic control and warning system and methods of the present invention make use of both centralized and distributed fuzzy logic controllers and calculations to control traffic flow. Furthermore, the outputs from one calculation are used as inputs to the second calculation. Traffic light phase-split messages are derived using a first fuzzy logic calculation. These calculations are based on real time traffic flow parameters and information. In attempt to avoid or minimize future aggravation of bad situations, second distributed fuzzy logic calculations are made at individual vehicles and for traffic warning signs. These calculations are based, in part on the results of the first traffic light and warning sign control fuzzy logic calculations, and also on each signs location and each vehicles current location, direction of travel, speed, etc.
It is therefore an object of this invention to provide new and improved traffic control systems and methods to improve the safety and reduce congestion on roadways.
It is a further object of this invention to provide an intelligent traffic light control system and method that incorporates fuzzy logic and expert systems technology to control the phase-splits of the traffic lights at intersections.
It is a further object of this invention to obtain traffic information from various sources and determine congestion parameters and warning information based on the obtained traffic information and to further determine appropriate action to be taken based on the congestion parameters and the warning information.
It is a further object of the invention to use fuzzy logic, intelligent systems, or expert systems to control and optimize the operations and processes of the present invention.
It is also an object of the invention to use fuzzy logic to determine congestion parameters and warning information.
It is also an object of the invention to use fuzzy logic to determine appropriate action such as appropriate traffic control action or appropriate traffic information distribution.
It is also an object of the invention to use fuzzy logic to derive warning information.
It is a further object to integrate intelligent traffic control signs for the display of traffic warning and direction signals to inform drivers of dangerous or congested traffic situations to be avoided and for such signs to operate in coordination with fuzzy logic derived traffic light control signals.
It is still a further object of this invention to use GPS satellite location signals to accurately locate vehicles and to use vehicle location, direction of travel, and velocity information to allow vehicle controllers to selectively respond to radio transmitted warning messages and advice for avoiding dangerous or congested areas.
It is yet another object to provide a traffic control and warning system and method that operates with multiple control centers wherein individual vehicles communicate with a selected center depending on the vehicles GPS coordinates and the location of the vehicles and the various control centers.
It is another object to use GPS technology to accurately track the location of emergency vehicles, to use this information to better control the traffic surrounding an emergency vehicle, and to use this information to provide warnings to motorists of approaching emergency vehicles.
It is another object to permit vehicles to communicate with multiple control centers with cellular telephone like handoff procedures as the vehicle travels from the area of one control center to that of another control center.
It is still another object to integrate fuzzy logic control of individual traffic lights with GPS warning and control messages transmitted from central controllers to individual vehicles with displayed vehicle warnings based on the calculated locations of those vehicles.
It is another object to select particular fuzzy logic inference rules for traffic light control based on particular conditions that may affect traffic flow such as weather or predicted unusual traffic conditions such as those that might be encountered with special events such as major sport attractions.
Yet another object is to select particular fuzzy logic inference rules for the distribution of traffic/danger warnings.
Further objects of the invention are apparent from reviewing the summary of the invention, detailed description, and claims set forth below.